IT Managers and Directors are well aware when they have Technical Debt issues in Salesforce. This typically happens when a company has used Salesforce for at least 2-3 years with multiple Consultants, Vendors, Developers, and Admins.
The following 3 Reasons typically prevent IT Managers and Directors from taking action:
1. Do not have the right Resources
Most Salesforce Support teams have a combination of Admins, a Business Analyst, and possibly a Developer. This allows them to support day-to-day requests such as Adding Users, Adding new Fields, Basic Reports and Dashboards, and other Salesforce Configuration Items. What support teams typically do not have is a Senior Technical Architect or Salesforce Expert that can go "Underneath the Hood" to analyze what is truly doing on with the system, and where items need to be addressed.
2. Lack of Time
Even if an IT Manager has an experienced Salesforce Architect or SME to perform an Assessment, there are most likely many other projects that the team is currently working on. These projects typically take priority as they will likely be critical business initiatives that automate new processes and support new products to increase revenue or reduce cost.
3. Don't know How to do an Assessment
There are best practices on the areas of the Salesforce Platform to analyze while doing a Salesforce Assessment. It takes time to research and plan on "How" to do the assessment, what areas should be looked at, and what the "Outputs" will be from the Assessment.
Without a Salesforce Assessment, the Technical Debt turns into production issues, outages, and increased cost to every enhancement project. It's like a cavity...taking care of it early on prevents the "Debt" from turning into a root canal.